The invention involves a composite beam, including edged, round timber sections connected by nail plates.
Existing composite beams of this type consist of rectangular or square prismatic beams trimmed on all sides. Manufacture of these beams starts from the smaller diameter at the top or head of the trunk. This makes the diameter at the base relatively greater, depending on the length of the beam, resulting in an increase in the bearing cross-section at the base. The diameter per running meter can increase or decrease by 1 cm. Due to this taper or conicity, a tree trunk 10 meters long can thus have a diameter differential of about 10 cm between head and base.
The existing nail plates used for joining the beams have been found to be in need of improvement, since it has been shown that vibration and peak loads cause the nails to loosen, thereby reducing the bearing strength of the composite beam.